This invention relates to a process for improving the quality of coal-derived liquids and more particularly to a process for improving the diesel fuel quality of coal-derived liquids.
The supply of domestic petroleum stocks, in comparison with demand, has been declining over the years. The need for a supplemental source of liquid hydrocarbon fuels is becoming clearly apparent. Domestic coal deposits appear to provide one such source for such hydrocarbon fuels.
Coal derived liquids are those liquids derived from coal by a variety of processes, including hydrogenation, H-donor solvent reactions, destructive distillation, pyrolysis in the presence or absence of hydrogen and extraction in various solvents.
The production of gasoline from coal-derived liquids is well known in the art. In fact, current process schemes, in the liquefaction of coal, emphasize gasoline as the major liquid product. U.S. Pat. Nos. 3,018,241, 3,018,242, 3,117,921, 3,143,489, and 3,700,586 are representative of such processes.
Recently, in addition to gasoline, there has been high demand for diesel fuel. However, because an acceptable cetane number distillate is difficult to achieve without very high hydrogen costs, the production of acceptable fuels from coal-derived liquids has not been, until the present invention, a feasible alternate route to diesel fuel production.